Question: Only nine out of the original thirteen colonies had to ratify the U.S. Constitution in order for it to take effect. What is this ratio, nine to thirteen, rounded to the nearest tenth?
Solution: Note that $\frac{7.8}{13} = 0.6$ and $\frac{9.1}{13} = 0.7.$ Since $\frac{9}{13}$ is closer to $\frac{9.1}{13}$ than to $\frac{7.8}{13},$ $\frac{9}{13}$ rounds to $\boxed{0.7}.$